1.1.b Flashcards
Atria
Blood enters, atria contract and squeeze it into ventricles
Muscular Walls of the heart
Thin around the atria, thick around ventricles (especially left!!) , pushes blood into ventricle
Ventricles
Need to push blood to a further distance, require more force
Right ventricle
Pushes blood into pulmonary artery
Left ventricle
Pushes blood into aorta
Aorta
Biggest artery in body, sends blood around every part of body
Atrioventricular valves
the valves between atria and ventricles (tricuspid and bicuspid valves)
Semilunar valves
the valves between the
ventricles and the bloods ‘exit point’ of the heart
Veins
Carry blood towards the heart
Arteries
Carry blood away from heart
Vena cava
Biggest veins in body
Superior ->returns blood above heart
Inferior -> returns blood below heart
Pulmonary artery
Sends used blood (full of waste products and lactic acid) to lungs that cleans & replace it with fresh oxygen
Lungs
Send the new washed blood back to the heart through pulmonary veins
Pulmonary veins
bring the new blood back to the heart, which enters through the left atrium, which pushes the blood down into the left ventricle, which sends it up to the Aorta.
Aorta
sends the new blood, rich in oxygen, away from the heart, around the body to all our muscles and organs
Heart values
Heart rate, stroke volume, cardiac output
Heart rate
Bpm.
Resting; between 60-100
Stroke volume
Amount of blood pumped out of heart (left ventricle)
Avg: 70ml
Cardiac output (Heart rate * stroke value )
Volume blood pumped out of heart per min (l/min)
Cardiac cycle
The transport of blood to the lungs and other working muscles of the body
Diastole
Lub (heart relaxes and fills with blood)
Systole
Dub (heart contracts and ejects blood)
Atrial systole
atria contract which forces blood into the ventricles
Ventricular systole
ventricles contract which pushes blood out of the heart to the pulmonary artery and aorta.
Conduction system
Myogenic/intrinsic
signal is sent across the heart by the cardiac muscles
Sino-atrial node
often called the ‘pacemaker’. Regulates the heart rate in line with the body’s demand. Sends out an electrical stimulus which travels across the muscle cells in the atria, causing the atria to contract (atrial depolarisation)
Atrioventricular-node
The impulse travels to the AV node, where it delays the next contraction to allow the ventricles to fully fill with blood. Once the AV valves have closed, the stimulus travels to the bundle of His and Purkinje fibres.
The bundle of His
are found in the ventricular walls and cause ventricular contraction as a result of conducting the electrical impulse in the ventricles (ventricular depolarisation)
Purkinje fibres
The stimulus travels down the bundle of His, which is a group of conduction cells. This separates into the right and left branches which consist of the Purkinje fibres
Atrial depolarisation
The effect that the SA node has on the atria, causing them to contract by providing an electrical stimulus across them
Ventricular depolarisation
the effect that the AV node has on the ventricles, causing them to contract by providing an electrical stimulus